The mobile service provider network supports many applications that a customer can access using their cell phone. These applications allow the customer to check their account balance, make payments, change rate plans and many more. In addition to applications, the mobile service provider network also has an infrastructure that allows the customer to download files to his cell phone. These files could be music, video, or firmware updates. The customer accesses these applications and file downloads through the public Internet.
When a client connects directly to a web server to download a file, the web server will send back to the client the length of the file before the server starts downloading the file. The file length is contained in an HTTP header variable called “Content-length”. If the client program knows the length of the file that is being downloaded, it can then calculate what percentage of the file has been downloaded so far. This information can be displayed to the user in a progress bar, for example.
The network of a mobile service provider such as, for example, Verizon Wireless™, allows customers to download many different files to their mobile device through a routing server named datapower. The datapower is a product division within IBM that produces a network device that specializes in XML transformations, routing and security. The datapower 35 is one brand from the IBM product division. The main function of the datapower in the mobile service provider network of our example is for URI routing. The reason that routing is necessary is because different groups of machines handle different types of requests.
The problem is that datapower, which receives the requests for file download from the customer and replies back to such requests from the customer, filters out the HTTP header “Content-Length”. This means that the client device cannot display progress bars. Not having the progress bars displayed is a problem for the customer. The files being downloaded can be over 50 mega bytes in size. Also, the speed of a wireless Internet connection can very based on the strength of signal or amount of traffic. These two factors make the task of downloading a file take from several minutes to several hours. Therefore, it is important for the customer to see that progress is being made.
Furthermore, some mobile devices, such as, for example, Motorola™ “Calgary” device require the HTTP header file content-length information passed to it when it downloads a music or video file. Since video and music files can be quite large, these mobile devices require first determining if they have enough space to download a file before allowing the client to get the file. In the event the file length is not passed to the device, the device displays to the user an error message “Unknown file size error” and does not let the user download the file.
Therefore, there is a need to solve the problem of datapower filtering out the HTTP header “Content-Length” as this would cause wireless devices to not be able to display a progress bar when downloading a file and may prevent the download music or video files to some types of mobile devices.